A plurality of grinders for grinding food, in particular coffee beans, is known per se, wherein the latter are always broken between two grinding elements, which are moved against each other. As a function of the design of the grinders, a differentiation is made between conical grinders and disk grinders.
Conical grinders are thus known in particular from EP 2 050 375 A1, from DE 195 14 794 A1, from DE 196 38 824 A1 (in particular FIG. 16 and description column 9, lines 43 et seqq. therein) and from DE 849 600 (in particular according to FIG. 2 and description page 2, lines 38 et seqq. therein).
In general, conical grinders of the state of the art encompass a first grinding element, which is designed in a conical manner and which is thus also called grinding cone. Said grinding cone is supported so as to be rotatable about an axis of rotation. A second grinding element, which is identified as grinding ring, is arranged coaxially to this axis of rotation and substantially around the tapered surface of the grinding cone. On its inner side, which is spaced apart from the grinding cone by embodying a grinding slit, the grinding ring also encompasses a substantially conical shape. On their sides located opposite one another, the grinding cone as well as the grinding ring have spirally arranged grinding surfaces, which are formed by teeth. In response to operation of a coffee machine, which is equipped with a conical grinder, the coffee beans, which are to be ground, are transported from an entrance area or entrance slit, respectively, of the grinder, to the exit area or exit slit thereof, respectively, by means of relative movement of the grinding cone with respect to the grinding ring through the grinding grooves, which are embodied between the teeth. During this transport, the individual coffee beans are moved against the respective grinding surfaces of the teeth and are comminuted by them by means of clamping. To ensure the comminution of the coffee beans, each grinding surface of the grinding cone is arranged such that it defines one of the grinding grooves of the grinding cone at a “rear” side of the respective grinding groove—with regard to the direction of the relative movement of the grinding cone relative to the grinding ring. Accordingly, each grinding surface of the grinding ring is arranged such that it defines one of the grinding grooves of the grinding ring at a “rear” side of the respective grinding groove—with regard to the direction of the relative movement of the grinding ring relative to the grinding cone.
In the case of disk grinders, which are known, for example, from DE 196 38 824 A1 (in particular FIG. 1 and description column 7, lines 26 et seqq. therein) as well as from DE 38 03 619 C2, the first grinding element and the second grinding element are in each case embodied in a substantially disk-shaped manner (as so-called grinding disks). The two grinding disks (hereinbelow also referred to as “first grinding disk” and “second grinding disk”) are arranged parallel to one another about a common axis of rotation by embodying a grinding slit and in each case encompass grinding surfaces, which are formed by teeth, on their opposite sides. In response to operation of a coffee machine, which is equipped with a disk grinder, the coffee beans, which are to be ground, are transported from an entrance area or entrance slit, respectively, of the grinder, to the exit area or exit slit thereof, respectively, by means of relative movement of the two grinding disks through the grinding grooves, which are embodied between the teeth. During this transport, the individual coffee beans are moved against the respective grinding surfaces of the teeth and are comminuted by them by means of clamping. To ensure the comminution of the coffee beans, each grinding surface of the first grinding disk is arranged such that it defines one of the grinding grooves of the first grinding disk at a “rear” side of the respective grinding groove—with regard to the direction of the relative movement of the first grinding disk relative to the second grinding disk. Accordingly, each grinding surface of the second grinding disk is arranged such that it defines one of the grinding grooves of the second grinding disk at a “rear” side of the respective grinding groove—with regard to the direction of the relative movement of the second grinding disk relative to the first grinding disk.
The grinding level, that is, the granulation of the ground coffee powder, can be adjusted via the distance of the two grinding elements relative to one another, via the number of the teeth as well as the height and angle of inclination thereof, among others. In particular, provision can be made for the number of the teeth to increase from the entrance area of the grinder to the exit area thereof, while the height of the respective teeth decreases from the entrance area to the exit area thereof. The known principle of comminuting the coffee beans is maintained in any event.
The design of the teeth or of the grinding surfaces, respectively, of known grinders will be explained below in an exemplary manner by means of publication DE 196 38 824 A1 (see FIG. 16 and FIG. 1 therein).
To simplify and standardize the illustration below, the following convention shall apply for conical grinders comprising two grinding elements in the form of a grinding cone and of a grinding ring of the above-mentioned type (for grinders of the state of the art as well as for the grinders according to the invention):                Point P:        This is a fictitious point P on a grinding surface of one of the grinding elements of the grinder, in particular on a cutting edge.        Axis of Rotation R:        At least one of the grinding elements and in particular the point P rotates about this axis of rotation, relative to the respective other grinding element on a circular path.        Direction of Rotation M:        This is the direction, about which the grinding element, which rotates about the axis of rotation R, moves.        Grinding Direction S:        This is the direction of movement of the point P in response to a rotation of one of the grinding elements in the direction of rotation M (this direction of movement is located on a tangent through the point P to the circle, on which the point P moves about the axis of rotation R relative to the respective other grinding element). Due to the fact that each of the grinding elements moves relative to the respective other grinding element, the two grinding elements act in different directions on a coffee bean. This is why a differentiation will be made below, if necessary, between a grinding direction S1 for a point P on one of the grinding elements and a grinding direction S2 for a point P on the other one of the grinding elements.        Tool Reference Plane E-I:        This is a plane in point P, which is embodied parallel to the grinding direction S and parallel to the axis of rotation R.        Assumed Working Plane E-II:        This is a plane, which is oriented orthogonally to the axis of rotation R and parallel to the grinding direction S, through the point P.        Grinding Edge Plane E-III:        This is a plane through the point P, which stands vertically on the tool reference plane E-I and vertically to the grinding direction S.        Angle of Inclination φ:        This is the angle between the grinding surface and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S. The angle of inclination φ is positive, when viewed originating from the grinding surface counter-clockwise in the direction of the tool reference plane E-I or in the direction of the grinding direction S, respectively.        
In this document, which is at hand here, FIG. 16, which is known from DE 196 38 824 A1 and which shows a conical grinder, is represented as FIG. 1, wherein the grinding cone 11 and the grinding ring 15 are illustrated separate from one another (in an exploded illustration, in which the grinding ring 15 is spaced apart from the grinding cone 11 further in the direction of the axis of rotation R), whereby it is assumed that the grinding cone 11 rotates relative to the grinding ring 15 about the axis of rotation R, which is illustrated in FIG. 1. The axis of rotation R and the direction of rotation M can be seen well in this figure.
The grinding direction S1 as well as the tool reference plane E-I, the working plane E-II and the grinding edge plane E-III are delineated on a freely chosen point P on the grinding surface 30 of the grinding cone 11. A point P, at which the corresponding grinding direction S2 as well as the tool reference plane E-I, the working plane E-II and the grinding edge plane E-III are delineated, is also chosen freely on a grinding surface 31 of the grinding ring 15. With regard to the grinding directions S1 and S2, it is important to note that, if the grinding cone 11 is rotated in the direction of rotation M about the axis of rotation R, the grinding ring 15 rotates relative to the grinding cone 11 in a direction of rotation opposite to the direction of rotation M. Accordingly, the grinding direction S1 is oriented in the direction of rotation M and the grinding direction S1 is oriented opposite to the direction of rotation M.
A section through the grinding cone 11, which is shown on the bottom in FIG. 1, can be seen in top view in FIG. 2, wherein the cut surface through the point P is located in the assumed working plane E-II. The angle of inclination φ of the grinding surface 30, thus the angle between the grinding surface 30 and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S1, is smaller than 90°.
The same applies with regard to the grinding surface 31 of the grinding ring 15 at the point P on the grinding surface 31 according to FIG. 1: the angle of inclination of the grinding surface 31, thus the angle between the grinding surface 31 and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S2, is smaller than 90° (not illustrated in the figures).
The disk grinder of FIG. 10 of DE 196 38 824 A1 is shown in FIG. 3 of this document. As mentioned above, the disk grinder encompasses the first disk-shaped grinding element 11′ (referred to hereinbelow as grinding disk 11′) and the second disk-shaped grinding element 15′ (referred to hereinbelow as grinding disk 15′). Coffee beans 3 are located in the grinding slit embodied between the grinding disks 11′, 15′. It is furthermore assumed that the grinding disk 11′ carries out a rotation about the axis of rotation R in a direction of rotation M relative to the grinding disk 15′. In response to the rotation of the grinding disk 11′ (relative to the grinding disk 15′) about the axis of rotation R in direction of rotation M, the coffee beans 3 are clamped and broken between a grinding surface 30, which is embodied at the first grinding disk 11′, and a grinding surface 31, which is embodied at the second grinding disk 15′. An arbitrary point P is also defined in FIG. 3 in each case for the upper grinding disk 15′ and the lower grinding disk 11′ on the grinding surface 30 or an arbitrary point P is defined on the grinding surface 31, respectively.
The two grinding disks 11′, 15′ extend substantially vertically to the axis of rotation R. This is why the grinding surfaces 30 and 31 of the grinding disks 11′, 15′ extend substantially parallel to a plane, which is arranged vertically to the axis of rotation R.
To simplify and standardize the illustration below, the following conventions shall apply for disk grinders comprising two grinding elements in the form of grinding disks of the above-mentioned type (for grinders of the state of the art as well as for the grinders according to the invention):                Point P:        This is a fictitious point P on a grinding surface of one of the (two) grinding elements, in particular on a cutting edge.        Axis of rotation R:        At least one of the grinding elements and in particular the point P rotates about this axis of rotation, relative to the respective other grinding element on a circular path.        Direction of rotation M:        This is the direction, about which the grinding element, which rotates about the axis of rotation R, moves (relative to the respective other grinding element).        Grinding direction S:        This is the direction of movement of the point P in response to a rotation of one of the grinding elements in the direction of rotation M (this direction of rotation is located on a tangent through the point P to the circle, on which the point P moves about the axis of rotation R relative to the respective other grinding element). Due to the fact that each of the grinding elements moves relative to the respective other grinding element, the two grinding elements act in different directions on a coffee bean. This is why a differentiation will be made below, if necessary, between a grinding direction S1 for a point P on one of the grinding elements and a grinding direction S2 for a point P on the other one of the grinding elements.        Tool reference plane E-I:        This is a plane in point P, which is embodied parallel to the grinding direction S and vertically to the axis of rotation R.        Assumed working plane E-II:        This is a plane, which is oriented parallel to the axis of rotation R and parallel to the grinding direction S, through the point P.        Grinding edge plane E-III:        This is a plane through the point P, which stands vertically on the tool reference plane E-I and vertically to the grinding direction S.        Angle of inclination φ:        This is the angle between the grinding surface and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S of the grinding surface. The angle of inclination is positive, when viewed originating from the grinding surface counter-clockwise in the direction of the tool reference plane E-I or in the direction of the grinding direction S, respectively.        
Based on the above-specified conventions for disk grinders, the grinding direction S1 for the grinding surface 30 of the first grinding disk 11′ and the grinding direction S2 for the grinding surface 31 of the second grinding disk 15′ and the tool reference planes E-I, the assumed working planes E-II and the grinding edge planes E-III are furthermore delineated—in each case for the point P illustrated in FIG. 3 on the grinding surface 30 of the first grinding disk 11′ and for the point P illustrated in FIG. 3 on the grinding surface 31 of the second grinding disk 15′.
With regard to the grinding directions S1 or S2, respectively, of the grinding surface 30 or 31, respectively, of the first grinding disk 11′ or of the second grinding disk 15′, respectively, it is important to note that, if the first grinding disk 11′ is rotated in the direction of rotation M about the axis of rotation R, the second grinding disk 15′ rotates relative to the first grinding disk 11′ in a direction of rotation opposite to the direction of rotation M. Accordingly, the grinding direction S1 is oriented in the direction of rotation M and the grinding direction S2 is oriented opposite to the grinding direction M.
In the state of the art shown herein, the angle of inclination φ for the grinding surface 30 and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S1, is also smaller than 90°, as can easily be seen in FIG. 3.
In the state of the art shown herein, the angle of inclination φ for the grinding surface 31 and the tool reference plane E-I, measured at the assumed working plane E-II in the grinding direction S2, is accordingly also smaller than 90°, as can easily be seen in FIG. 3.
It can thus be noted that conical grinders of the state of the art comprise the following features:                a grinding cone, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a first grinding surface, which adjoins the grinding edge,        a grinding ring, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a second grinding surface, which adjoins the grinding edge,        wherein the grinding cone and the grinding ring are arranged coaxially along a common axis of rotation by forming a grinding slit, which extends between the grinding cone and the grinding ring,        wherein the grinding cone and the grinding ring are configured to be rotated relative to one another about the common axis of rotation, so that, in response to a rotation of the grinding cone relative to the grinding ring, each first grinding surface of the grinding cone is in each case moved in a grinding direction relative to the grinding ring, so as to transport the coffee beans, which are to be ground, from an entrance slit of the grinder in the grinding grooves of the grinding cone and of the grinding ring through the grinding slit to an exit slit, which is arranged below the entrance slit, and to comminute them by means of the first grinding surfaces of the grinding cone, wherein each first grinding surface is arranged such that it defines one of the grinding grooves of the grinding cone at a rear side of the respective grinding groove relative to the grinding direction,        wherein each of the first grinding surfaces of the grinding cone (11) encompasses an angle of inclination φ at an arbitrary point at the respective first grinding surface, relative to a tool reference plane, measured at an assumed working plane in the grinding direction of the respective first grinding surface,        wherein the tool reference plane is a plane in the arbitrary point, which is embodied parallel to the grinding direction and parallel to the common axis of rotation, and        wherein the assumed working plane is a plane, which is oriented orthogonally to the axis of rotation and parallel to the grinding direction, through the arbitrary point.        
It can furthermore be noted that conical grinders of the state of the art comprise the following features:                a grinding cone, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a first grinding surface, which adjoins the grinding edge,        a grinding ring, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a second grinding surface, which adjoins the grinding edge,        wherein the grinding cone and the grinding ring are arranged coaxially along a common axis of rotation by forming a grinding slit, which extends between the grinding cone and the grinding ring,        wherein the grinding cone and the grinding ring are configured to be rotated relative to one another about the common axis of rotation, so that, in response to a rotation of the grinding ring relative to the grinding cone, each second grinding surface of the grinding ring is in each case moved in a grinding direction relative to the grinding cone, so as to transport the coffee beans, which are to be ground, from an entrance slit of the grinder in the grinding grooves of the grinding cone and of the grinding ring through the grinding slit to an exit slit, which is arranged below the entrance slit, and to comminute them by means of the second grinding surfaces of the grinding ring, wherein each second grinding surface is arranged such that it defines one of the grinding grooves of the grinding ring at a rear side of the respective grinding groove relative to the grinding direction,        wherein each of the second grinding surfaces of the grinding ring encompasses an angle of inclination φ at an arbitrary point at the respective second grinding surface, relative to a tool reference plane, measured at an assumed working plane in the grinding direction of the respective second grinding surface,        wherein the tool reference plane is a plane in the arbitrary point, which is embodied parallel to the grinding direction and parallel to the axis of rotation, and        wherein the assumed working plane is a plane, which is oriented orthogonally to the axis of rotation and parallel to the grinding direction, through the arbitrary point.        
It can furthermore be noted that disk grinders of the state of the art encompass the following features:                a first grinding disk, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a first grinding surface, which adjoins the grinding edge,        a second grinding disk, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a second grinding surface, which adjoins the grinding edge,        wherein the first grinding disk and the second grinding disk are arranged coaxially along a common axis of rotation by forming a grinding slit, which extends between the first grinding disk and the second grinding disk and which in each case extend substantially vertically to the common axis of rotation,        wherein the first grinding disk and the second grinding disk are configured to be rotated relative to one another about the common axis of rotation, so that, in response to a rotation of the first grinding disk relative to the second grinding disk, each of the first grinding surfaces of the first grinding disk is in each case moved in a grinding direction relative to the second grinding disk, so as to transport the coffee beans, which are to be ground, from an entrance slit of the grinder in the grinding grooves through the grinding slit to an exit slit, and to comminute them by means of the first grinding surfaces of the first grinding disk, wherein each first grinding surface of the first grinding disk is arranged such that it defines one of the grinding grooves of the first grinding disk at a rear side of the respective grinding groove relative to the grinding direction,        wherein each first grinding surface of the first grinding disk encompasses an angle of inclination φ at an arbitrary point at the respective first grinding surface, relative to a tool reference plane, measured at an assumed working plane in the grinding direction of the respective first grinding surface,        wherein the tool reference plane is a plane in the arbitrary point, which is embodied parallel to the grinding direction and vertically to the axis of rotation, and        wherein the assumed working plane is a plane, which is oriented parallel to the axis of rotation and parallel to the grinding direction, through the arbitrary point.        
Finally, it can be noted that disk grinders of the state of the art encompass the following features:                a first grinding disk, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a first grinding surface, which adjoins the grinding edge,        a second grinding disk, which has a number of teeth, which are spaced apart from one another and which are separated from one another by grinding grooves and which in each case encompass a grinding edge and a second grinding surface, which adjoins the grinding edge,        wherein the first grinding disk and the second grinding disk are arranged coaxially along a common axis of rotation by forming a grinding slit, which extends between the first grinding disk and the second grinding disk and which in each case extend substantially vertically to the common axis of rotation,        wherein the first grinding disk and the second grinding disk are configured to be rotated relative to one another about the common axis of rotation, so that, in response to a rotation of the second grinding disk relative to the first grinding disk, each of the second grinding surfaces of the second grinding disk is in each case moved in a grinding direction relative to the first grinding disk, so as to transport the coffee beans, which are to be ground, from an entrance slit of the grinder in the grinding grooves through the grinding slit to an exit slit, and to comminute them by means of the second grinding surfaces of the second grinding disk, wherein each second grinding surface of the second grinding disk is arranged such that it defines one of the grinding grooves of the second grinding disk at a rear side of the respective grinding groove relative to the grinding direction,        wherein each of the second grinding surfaces of the second grinding disk encompasses an angle of inclination φ at an arbitrary point at the respective second grinding surface, relative to a tool reference plane, measured at an assumed working plane in the grinding direction of the respective second grinding surface,        wherein the tool reference plane is a plane in the arbitrary point, which is embodied parallel to the grinding direction and vertically to the axis of rotation, and        wherein the assumed working plane is a plane, which is oriented parallel to the axis of rotation and parallel to the grinding direction, through the arbitrary point.        